Einfluß der Holzabmessungen auf die Zugfestigkeit von Bauschnittholz

The effect of timber dimensions on tensile strength was investigated in 750 and 200 tests involving spruce and Douglas fir respectively, with dimensions ranging in thickness from 30 mm to 70 mm, in width from 50 mm to 200 mm, and in length from 150 mm to 2,500 mm. Results show tensile strength to be essentially related to knot ratio and density and to decrease with increasing length, in accordance with relationship f_t,1 = f_t,0 ·(l₀/l₁)^0.1. Since specimens tend to exhibit decreasing knot ratios with increasing width, tensile strength was shown to rise with increasing width. Apart from this relationship no significant effect of width and thickness on the 5-percentiles of tensile strength, as assumed e.g. in Eurocode 5, was detected.